Implantable medical devices such as speech processors and neurostimulators are typically battery-powered. Although battery technology for such devices continues to deliver ever-longer cell lifetimes, eventually the battery or batteries in an implantable device must be replaced or recharged. Because replacement requires surgical extraction of an implanted medical device, the use of rechargeable (“secondary”) batteries is increasingly favored. The battery of an implanted medical device can be recharged transcutaneously, with the device in situ and a battery charger positioned outside of tissue. Inductive charging units are used to recharge implanted batteries. Inductively recharging an implanted device's battery through the skin requires a patient to properly align a charger with respect to the device's recharging circuitry, and keep it there during the recharging period. One such inductance charging unit has a sending (primary) coil powered by a rechargeable cell and incorporates a metal detector to aid in location of a receiving (secondary) coil in an implanted device. The recharging is done daily, and can take up to an hour at a time. This procedure can be inconvenient, uncomfortable, and a source of anxiety for the patient, and requires him to remember to recharge the battery.